JPS6239543B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lead frame, and particularly to a lead frame used for assembling a single-line resin-sealed semiconductor device.

As shown in FIG. 1, one of the single-line resin-sealed semiconductor devices has recently been developed in which leads 2 extending from one side of a resin package (mold part) 1 are bent alternately on the left and right to form two rows of lead groups. is being developed. A lead frame 3 shown in FIG. 2 is used to assemble a semiconductor device having this structure.
This lead frame 3 is patterned by partially punching out a thin metal plate using photoetching technology or precision press technology. Further, generally, this pattern (lead pattern) is formed in 5 or 7 series, etc., to form one lead frame. The lead pattern includes two wide main frames 4 extending in parallel along the longitudinal direction of the lead frame 3, two sub-frames 5 connecting the main frames 4, and a central part of one of the sub-frames 5. A rectangular tab 7 supported via a short tab lead 6, and a plurality of leads 2 extending parallel to the main frame 4 from the other sub frame 5.
and dams 8 arranged in a row that connect these leads 2 and also connect to the main frame 4. Further, a portion of the lead 2 that is distal from the dam 8 is bent and extends toward the tab 7. Further, a positioning hole 9 is bored in at least one main frame 4 corresponding to the side of the tab 7. When assembling the semiconductor device, the circuit element (pellet) 10 is fixed on the tab 7, and the electrode of the pellet 10 and the tip of the corresponding lead 2 are connected using the wire 11. The area having the tab 7 surrounded by the pair of main frames 4, the dam 8 and one of the sub-frames 5 is molded with resin and covered with the mold part 1, and then the tab lead 6 is separated and the unnecessary dam 8 and main frame are removed.・Cut and remove the sub-frames 4 and 5. Thereafter, the leads 2 protruding from one side of the mold part 1 are alternately bent to the opposite side to manufacture a semiconductor device as shown in FIG.

Incidentally, even when producing a new semiconductor device, it is preferable to use existing equipment for assembly in order to reduce manufacturing costs. For this reason, if an attempt is made to match the width of the single-line lead frame to the existing equipment, the main frame 4 will become thinner as shown in FIG. 3 if the number of leads is large. This main frame 4 has a positioning hole 9 that serves as a guide when positioning the lead frame during assembly for pellet bonding, wire bonding, etc. (in order to use the existing equipment, it is necessary at the position indicated by the double-dashed chain line in the same figure)
is necessary, but when the main frame becomes thin like this,
There is an inconvenience that this positioning hole cannot be provided.

Therefore, an object of the present invention is to provide a positioning hole even if the main frame is thin, to make use of existing equipment, and to maintain miniaturization of the lead frame.

On the other hand, if the main frame 4 becomes thinner as described above, the main frame 4 will bend and protrude due to the resin injection pressure during resin molding, and the cutting blade will be securely covered when the main frame etc. is subsequently cut and removed. It does not come into contact with the cut object (part of the lead frame), resulting in poor work. Further, since the cutting blade cuts the resin, there are problems such as severe wear of the cutting blade and shortening of its life.

On the other hand, in the single line type lead frame 3, the leads 2 extend only in one direction, so the leads 2 located at the ends are bent and extended along the main frame 4 and the sub frame 5. . Furthermore, as the number of leads 2 increases, the width of each lead 2 has to become narrower because there is also a demand for miniaturization of semiconductor devices. For this reason, the cantilever type leads, especially the ends, become long and easily deform when subjected to external forces. External forces include contact with a worker or the like when handling the lead frame, or inflow pressure of resin during resin molding. If the lead is significantly deformed, the wire 11 may break. Further, when the lead 2 is deformed during the resin molding, it is pushed out, so that a part of the lead 2 is exposed from the mold part 1, which is unfavorable in terms of appearance. Furthermore, since the interface between the lead 2 and the resin is exposed, there is a risk that moisture will propagate through this interface and reach the pellet, resulting in poor characteristics.

Therefore, another object of the present invention is to provide a single-line lead frame that has a positioning hole even if the main frame is thin and is difficult to deform. The aim is to improve retention and reduce manufacturing costs.

In order to achieve these objects, the present invention provides a positioning hole in the lead, fixes the outermost lead, which is easily deformed, to the frame via a connecting piece to be cut, and fixes a thin frame part to the outermost lead. It is fixed and reinforced through a connecting piece to be cut,
The present invention will be explained below with reference to Examples.

FIG. 4 is a plan view of a lead frame according to an embodiment of the present invention. The lead frame 3 of this embodiment has almost the same pattern as the lead frame 3 shown in FIG. Since it is no longer possible to provide a positioning hole 9 directly in the main frame 4, and the outermost lead 2 is cantilevered and elongated, there is a connection between the main frame 4 and the sub-frame 5 to be cut, in order to increase the strength. The strength of the main frame 4 is increased by connecting the weak main frame 4 and the outermost lead 2 with the connecting piece 12 to be cut. A connecting piece 12 to be cut to be connected is provided right next to the tab 7, and a positioning hole 9 is provided across at least one of the connecting pieces 12 to be cut and the lead 2. Further, since the leads 2 are thin, it is difficult to immediately provide the positioning holes 9 in these areas simply by providing the connecting pieces 12 to be cut. Therefore, the lead portion where the positioning hole 9 is provided is partially widened. Therefore, the extending patterns of the successively adjacent leads are changed compared to the lead frame shown in FIG. 2. In addition, since the connecting piece 12 to be cut and the tab lead 6 are separated after molding, in order to easily break at that time, a groove (circular cross-section groove in FIG. 5) that causes stress concentration is formed along the cutting line. However, a U-shaped groove, a V-shaped groove, etc. may also be used.) 13 is provided.

To assemble a semiconductor device using such a lead frame, the pellet 10 is fixed on the tab 7, the electrode of the pellet 10 and the tip of the lead 2 are connected with the wire 11, and then the pellet 10,
The inner end of the lead etc. is molded with resin and covered with the mold part 1, and then the connecting piece 12 to be cut is inserted into the groove 1.
At the same time, the tab leads 6 are also separated. Further, the dam 8 and the main and sub-frames 4 and 5 are cut and removed, and the leads 2 protruding from the mold part 1 are bent alternately on the left and right sides to manufacture a desired semiconductor device as shown in FIG.

According to such a lead frame, as a result of using existing equipment even when the number of leads increases, positioning holes can be provided across the leads and the connecting part to be cut even if the main frame is thinner. Because of this, the positioning holes can be used to accurately and reliably position and fix the lead frame during assembly using pellet bonding, wire bonding, etc.
Therefore, the assembly is accurate and reliable, and the yield is improved.

In addition, by using this lead frame, the resin on the upper and lower surfaces of the lead is integrated through the positioning hole area, making it difficult for the lead to separate from the resin, and preventing moisture from flowing from the interface between the lead and the resin. It is possible to improve moisture resistance and prevent property deterioration without infiltration.

Further, according to this lead frame, the cantilever type outermost lead 2 is attached to the subframe 5 with the connecting piece 12 to be cut.
Since it is supported and reinforced through the wire, it will not be pushed outward by the inflow pressure of the resin during resin molding, and not only will the wire not break, but the side surface of the lead 2 will not be pushed out by the molded part. 1 will not be exposed and will not cause poor appearance.

In addition, the main frame 4, which has become thinner due to the use of existing equipment, is connected to the outermost lead 2 via the connecting piece 12 to be cut, and this is also reinforced, so that resin can be injected during resin molding. It does not bulge out or bend significantly even when subjected to pressure, and subsequent cutting of unnecessary lead frame parts becomes reliable. Furthermore, since the cutting blade does not come into contact with the resin, there is less wear on the cutting blade and its life is extended.

Note that the present invention is not limited to the above embodiments. That is, the lead width may be further increased so that the positioning hole is provided only in the lead.

As described above, according to the lead frame of the present invention, existing equipment can be used, and the manufacturing cost of semiconductor devices can be reduced.

Further, according to the present invention, the elongated leads and the thin frame portions are connected to each other by the connecting pieces to be cut. Therefore, a certain amount of external force will not cause deformation. Therefore, semiconductor devices can be assembled accurately and yields can be improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a single-line type semiconductor device, FIG. 2 is a plan view of a lead frame used when assembling the single-line type semiconductor device, and FIG.
The figure is a partial plan view of a lead frame with a thin frame, the fourth
The figure is a plan view of a lead frame according to an embodiment of the present invention, and FIG. 5 is an enlarged sectional view showing a connecting piece to be cut. 1...Resin package cage, 2...Lead, 3...
...Lead frame, 4...Main frame, 5...Subframe, 6
...Tab lead, 7...Tab, 8...Dam, 9...
...Positioning hole, 10...Pellet, 11...Wire, 12...Connecting piece to be cut, 13...Groove.

Claims (1)

[Claims] 1 A pair of main frames spaced apart from each other and extending along the longitudinal direction, a pair of sub-frames connected to the main frames and spaced apart from each other, and partitioned by the main frame and the sub-frame. 1. A lead frame having a tab and a plurality of leads in a section, wherein the outermost lead close to the main frame has a positioning hole and is fixed to the main frame and the sub frame.